Milk thistle, with its distinctive purple flowers and long, thorny leaves, has long been touted for its liver health benefits and detoxing prowess.

Milk thistle and its healing properties were first described by the Greek physician Dioscorides in 40 A.D. Dioscorides was a physician, pharmacologist, botanist, and the author of De Materia Medica, a five-volume Greek encyclopedia describing herbal medicines that was the leading pharmacological text for 16 centuries. He was employed as a physician and surgeon in the armies of Roman emperor Nero, which gave him the opportunity to travel extensively, studying the features, distribution, and medicinal properties of many plants and minerals.

Also known as silybum marianum, milk thistle is native to the Mediterranean region and is part of the daisy, or Asteraceae family. Milk thistle is found in the Eastern United States and California, South America, Africa, Australia, and Asia.

Milk thistle plants are able to grow up to 10 feet, with broad leaves with distinctive milky white veins. Some cultures believe the veins originated from a falling drop of the milk of the Virgin Mary, which is why it’s sometimes referred to as Our Lady’s thistle, blessed milk thistle, St. Mary’s Thistle, Holy thistle, Virgin thistle, and Christ’s crown.

Milk thistles are hardy plants and like to grow in dry, rocky soil, preferring full sun or slight shade. Milk thistle produces purple flower heads that bloom from June to August in the Northern Hemisphere or from December to February in the Southern Hemisphere.

Milk Thistle’s Medicinal Properties

For more than 2,000 years, milk thistle has been used as a liver tonic and to treat other liver diseases, such as jaundice, cirrhosis, hepatitis, and poisoning, as well as to cleanse the liver from alcohol and drug addiction. Milk thistle also stimulates the appetite, treats psoriasis, and is used by nursing mothers to increase milk production and lactation.

The medicinal properties of milk thistle come from the seeds inside the fruits which contain a bioflavonoid complex called silymarin consisting of silybin (also spelled ‘silibinin’), silydianin, and silychristin.

Liver Health and Detox

“Silybum marianum or milk thistle (MT) is the most well-researched plant in the treatment of liver disease,”  reads a research review published in Phytotherapy Research in 2010.

Milk thistle cleanses the liver of toxins, is used for overeating or overindulging in recreational drugs or alcohol, treats jaundice and cirrhosis, and has a protective effect on the liver, helping it to regenerate healthy liver cells after damage.

“Silymarin has been used to treat alcoholic liver disease, acute and chronic viral hepatitis, and toxin-induced liver diseases,” the review reads.

Because milk thistle is used to increase the secretion and flow of bile from the liver and gallbladder, it can be used for all problems involving the gallbladder, including the prevention and treatment of gallstones.

An Antidote to Poisoning

Milk thistle has been used to counteract many poisons for as long as 2,000 years, when early physicians used it to treat snake bites and other poisonings. In modern times, milk thistle has been used successfully against poisoning from death-cap mushrooms, an increasing problem in the United States since their accidental introduction from Europe.

Death-caps can be fatal, and medical treatment is essential within 72 hours of ingestion. Death-cap poisoning can cause acute liver failure, with one cap containing enough poison to kill a human being. Having milk thistle in your garden or yard is an excellent way to keep you and your family safe from accidental poisoning from various sources.

Cancer Protection

Milk thistle is also showing promise in the fight against cancer. A study in the World Journal of Gastroenterology shows that the primary bioactive compound found in milk thistle, silibinin, could suppress the growth of cancerous liver cells. The study shows that silibinin significantly reduced the development of several human hepatoma cell lines. They were also able to demonstrate that silibinin mediates anti-cancer liver effects by:

• reducing cancer cell proliferation and cell cycle progression.
• enhancing programmed death of cancer cells.
• altering the chromatin structure of the cancer cells.

This study indicates that silibinin could be used to prevent the development of liver cancer, which is one of the most common cancers worldwide.

Milk thistle has also been shown to stop the inflammatory chain known to promote the progression of lung cancer, a study published in Molecular Carcinogenesis found. Researchers found that tumor growth is halted when this chain is broken and metastatic growth stops. Silibinin from milk thistle was shown to break these inflammatory chain reactions. The study’s authors concluded that naturally-derived products such as silibinin may be as effective as today’s best treatments for lung cancer.

Boosts Milk Production for Breastfeeding Mothers

As a galactagogue (lactation inducer), milk thistle has long been known to help nursing mothers produce more milk for their babies. Galactagogues increase the flow of mother’s milk. A study shows that women treated orally with milk thistle’s famed bioflavonoid complex—silymarin—saw an 85.94 percent increase in daily milk production. No negative effects were reported, and it was very well tolerated by all the participants.

Helps Diabetes

According to the Centers for Disease Control and Prevention (CDC), approximately 37 million people in the United States have diabetes, which is more than 11 percent of the population. Thankfully, milk thistle has been shown to stabilize blood sugar levels and help with Type 2 diabetes, and it may offer a more natural solution for those struggling with the disease.

Clinical studies have demonstrated that the high antioxidant levels in milk thistle help decrease blood sugar levels in people with insulin resistance.

A study published in the Journal of Diabetes Research found that the antioxidant and anti-inflammatory properties of the silymarin from milk thistle drastically reduced fasting glucose levels in diabetic participants.

Another study from the Institute of Medicinal Plants found that diabetic patients given silymarin extract over a four-month period showed significantly improved fasting blood sugar and insulin levels compared to patients who received a placebo.

Diabetes is the body’s inability to either produce (Type 1) or respond to (Type 2) the hormone insulin, which results in too much sugar in the blood and urine. Because the liver plays a role in metabolizing hormones and releasing insulin into the bloodstream, milk thistle is likely helpful because of its healing and protective effects on the liver.

Milk Thistle in Chinese Medicine

In Chinese medicine, milk thistle is known as the herb da ji or shui fei ji (milk thistle seeds). Milk thistle works specifically on the liver, heart, and spleen and is considered bitter, cooling, and drying. Its actions are to remove stagnation (blockages), stop bleeding, stimulate qi (energy), benefit the skin, heal wounds, reduce swelling, promote urination, and strengthen the liver.

It’s milk thistle seeds that are used for their medicinal benefits. Da ji is available in capsule form and extracts, and tinctures can be found at many health food stores. If you can harvest milk thistle seeds from wildflowers, they can be ground and added to food or made into tea.

Risks and Side Effects

Milk thistle is generally considered very safe to use and has very few cases of reported side effects. That said, always use caution if you have any health conditions, are on medications, or have seasonal allergies, especially to any plants in the daisy or Asteraceae family. If you would like to begin taking milk thistle—or any other supplement—always start with smaller doses to see how you tolerate it, then increase the dosage slowly, paying close attention to any reactions. If any occur, discontinue use and consult with a health care practitioner.

Possible Drug Interactions

Certain medications have been known to interact with milk thistle, including allergy medications, blood thinners, and anti-anxiety drugs. Silymarin has also been shown to lower blood sugar. Although it has been proven helpful for diabetic patients, always consult your physician before taking milk thistle if you have diabetes or are on diabetes medications. As a general rule, you should consult with a health care practitioner before taking supplements if you’re on any medication.

Final Thoughts

In recent years, the popularity of milk thistle has increased, perhaps because of the public’s desire for more natural approaches to chronic diseases and the popularity of liver detoxing. In fact, a report has projected that the 10-year forecast for milk thistle supplements is estimated to be worth $204 million by 2032.

With milk thistle’s massive list of medicinal benefits and the public’s growing mistrust of Western drugs and treatments, it seems prudent to look to nature—where a large percentage of pharmaceutical drugs originate—to fulfill as many of our health needs as possible. Milk thistle is easily grown in most locations with ample sunlight, and harvesting its seeds can help with many health problems we now face in the modern world.

Because a healthy, well-functioning liver is vital to so many of the body’s processes, milk thistle—with its liver cleansing, detoxifying, and protective effects—seems like an excellent thing to have growing in your garden.

Emma Suttie is an acupuncture physician and founder of Chinese Medicine Living—a website dedicated to sharing how to use traditional wisdom to live a healthy lifestyle in the modern world. She’s a lover of the natural world, martial arts, and a good cup of tea.